John and Ed were approaching Black Rock desert on the way to Burning Man when the email arrived from a friend. “Thanks for letting us stay in your apartment this weekend!”

John looked at his husband in confusion. There must be some mistake – they had left their San Francisco apartment with their professional housesitter.

“No, it’s definitely your house – your car, your wedding photos, your cats,” said his friend. “We found it on Airbnb.”

In what is just the latest symptom of San Francisco’s overheated property market, John and Ed discovered that their housesitter had rented out their apartment while they were away, charging $2,000 for five days.